This application is based on a Japanese Patent Applications Hei. 11-304734 filed on Oct. 26, 2000, Hei. 11-322700 filed on Nov. 12, 1000 and 2000-182211 filed on Jun. 16, 2000, herein cooperated by reference.
1. Field of Application
The present invention relates to an electromagnetic relay constituted by a yoke, a coil portion wound onto the yoke, an armature toggled and provided with respect to the yoke, and a moving contact and a fixed contact which are brought into a contact and separation state depending on the toggle motion of the armature.
2. Related art
FIGS. 1 to 3 show a conventional electromagnetic relay of this type. The electromagnetic relay comprises a yoke C having a winding space divided by a coil bobbin A, a coil B wound thereon and magnetic pole portions C1 and C2 provided on both ends, a pair of armatures D1 and D2 which are attracted into and separated from the magnetic pole portions C1 and C2 of the yoke C to be rotated depending on the excitation state of the coil B, a fixed contact plate E provided with a fixed contact E1, a movable spring F provided with a moving contact F1 opposite to the fixed contact E1, and a card G linked to the armatures D1 and D2 for displacing the movable spring F such that the moving contact F1 abuts on or separates from the fixed contact E1 depending on the rotating operation of the armatures D1 and D2.
The yoke C forms a coil block CC together with the coil bobbins A and B. Moreover, the armatures D1 and D2 interpose a permanent magnet H therebetween, and is formed of a molding material integrally with the permanent magnet H. Thus, an armature block DD is formed. A portion J thus formed integrally is provided with a support portion J1 rotatably supported on a body K in which parts such as the armature block DD and the coil block CC are arranged, and furthermore, is provided with a lever J2 extended and linked to one of ends of the card G having the other end connected to the movable spring F.
The lever J2 is connected to the yoke C through an adjusting spring L to be rotatably supported in a state in which a clearance GG is formed between both magnetic pole portions C1 and C2 of the yoke C respectively. The clearance GG between the magnetic pole portions C1 and C2 of the yoke C and the armatures D1 and D2 is regulated by properly changing the shape of the adjusting spring L. By thus regulating the clearance GG, a working voltage of the abutting and separating operation of both contacts E1 and F1 can be regulated so that a sensitivity of the abutting and separating operation of the contacts E1 and F1 can be regulated.
When a current is caused to flow in a preset direction so that the coil B is excited, an end D11 of the armature D1 is attracted into the magnetic pole portion C1 on one end of the yoke C and the other end D22 of the armature D2 is attracted into the magnetic pole portion C2 on the other end of the yoke C such that a closed magnetic circuit is formed. Consequently, the armature block DD is rotated clockwise in FIG. 17. As a result, the card G linked to the lever J2 of the armature block DD is driven toward the movable spring F, and the movable spring F connected to the driven card G is displaced toward the fixed contact plate E so that the moving contact F1 of the movable spring F abuts on the fixed contact E1 of the fixed contact plate E. When the excitation of the coil B is stopped, this state is held.
When a current is caused to flow in a direction reverse to the above-mentioned direction so that the coil B is excited in this state, an end D12 of the armature D1 is attracted into the magnetic pole portion C2 on the other end of the yoke C and one end D21 of the armature D2 is attracted into the magnetic pole portion C1 on one end of the yoke C such that a closed magnetic circuit is formed. Consequently, the armature block DD is rotated counterclockwise in FIG. 2. As a result, the card G linked to the lever J2 of the armature block DD is driven in such a direction as to go away from the movable spring F, and the movable spring F connected to the driven card G is displaced apart from the fixed contact plate E so that the moving contact F1 of the movable spring F is separated from the fixed contact E1 of the fixed contact plate E. When the excitation of the coil B is stopped, this state is held.
With such a structure, however, the armature block DD is positioned in three points, that is, the magnetic pole positions B1 and B2 and the fulcrum J1. Therefore, a variation in the dimensions of parts causes a clearance to be generated between the end of the magnetic pole portion C2 and the armature D22 of the armature block J in either of the magnetic pole positions B1 and B2 (the B2 side in an example of FIG. 3) as shown in FIG. 3. As a result, a fluctuation in a magnetic characteristic is increased so that a shock resistance is deteriorated. Moreover, it is very difficult to regulate a sensitivity.
In this phenomenon, the following troublesome are to be caused , as shown in FIG. 2, the clearance GG is formed in two portions between the armatures D1 and D2 and the magnetic pole portions C1 and C2 of the yoke C. Therefore, in a state in which the sensitivity of the abutting and separating operation of the contacts E1 and F1 is regulated, the clearance GG in at least one of the two portions remains so that a variation in suction force is increased. Consequently, it is hard to regulate the sensitivity of the abutting and separating operation of the contacts E1 and F1.
The invention has been made in consideration of the circumstances and has an object to provide an electromagnetic relay in which a fluctuation in a magnetic characteristic is small, a shock resistance is enhanced and a sensitivity can be regulated easily.
Another object is to provide an electromagnetic relay capable of easily regulating a sensitivity of the abutting and separating operation of both contacts.
In order to solve the problem, a first aspect of the invention is directed to an electromagnetic relay comprising a yoke having both ends bent in one direction, a coil portion wound onto a central part between the ends of the yoke, a permanent magnet provided between the ends of the yoke, an armature formed to have a greater length than that between the ends of the yoke and provided on the one direction side with respect to the permanent magnet, and a hinge spring capable of causing both end sides of the armature to be toggled with respect to the ends of the yoke, thereby integrally fixing the permanent magnet and the armature, wherein a protrusion is provided between the permanent magnet and the armature.
With such a structure, the position of the armature is determined by two points of the protrusion and either of the positions of magnet poles. Therefore, an unnecessary clearance is not generated so that a magnetic gap is not caused. Consequently, a fluctuation in a magnetic characteristic is reduced so that a shock resistance can be enhanced. Moreover, a sensitivity can be regulated easily.
The electromagnetic relay according to the first aspect of the invention may further comprise an auxiliary yoke formed like a plate having a length which is almost equal to the length between the ends of the yoke and provided on a side reverse to the one direction with respect to the permanent magnet, the permanent magnet being formed like a plate having a smaller length than that between the ends of the yoke, the armature being formed like a plate and having the protrusion on a face opposed to the permanent magnet, the hinge spring being formed to have a central part attached to a face on the one direction side in the armature and both side parts extended from the central part in a direction reverse to the one direction, attached to both side faces of the auxiliary yoke respectively, and having both side parts interposing the permanent magnet therebetween, and the permanent magnet, the armature and the auxiliary yoke being integrally fixed with the hinge spring. According to such a structure, a fluctuation in a magnetic characteristic is reduced so that a shock resistance can be enhanced. Moreover, a sensitivity can be regulated easily.
In the electromagnetic relay according to the first aspect of the invention, the permanent magnet may be formed like a plate having a length which is almost equal to that between the ends of the yoke, the armature may be formed like a plate and may have the protrusion on a face opposed to the permanent magnet, the hinge spring may be formed to have a central part attached to a face on the one direction side in the armature and both side parts extended from the central part in a direction reverse to the one direction and attached to both side faces of the permanent magnet respectively, and the permanent magnet and the armature may be integrally fixed with the hinge spring. According to such a structure, a fluctuation in a magnetic characteristic is reduced so that a shock resistance can be enhanced. Moreover, a sensitivity can be regulated easily. Furthermore, a size can be reduced still more.
The electromagnetic relay according to the first aspect of the invention may further comprise an auxiliary yoke formed like a plate having a length which is almost equal to the length between the ends of the yoke and provided on a side reverse to the one direction with respect to the permanent magnet, the permanent magnet being formed like a plate having a smaller length than that between the ends of the yoke, the armature being formed like a plate and having the protrusion on a face opposed to the permanent magnet, the hinge spring being formed to have a central part attached to a face on a direction side reverse to the one direction in the armature and both side parts extended from the central part in the reverse direction, attached to both side faces of the auxiliary yoke respectively and interposing the permanent magnet therebetween, and the permanent magnet, the armature and the auxiliary yoke being integrally fixed with the hinge spring. According to such a structure, a fluctuation in a magnetic characteristic is reduced so that a shock resistance can be enhanced. Moreover, a sensitivity can be regulated easily. Furthermore, it is possible to suitably prevent wear from being caused by a toggle motion of an armature block including the permanent magnet, the armature and the auxiliary yoke which are integrated with the hinge spring.
The electromagnetic relay according to the second or fourth aspect of the invention may further comprise a device body having a body and a cover, the auxiliary yoke having a fixing portion to the body. With such a structure, assembly can easily be carried out.
In the electromagnetic relay according to the fifth aspect of the invention, the fixing portion may include a plurality of protrusions and the body may be provided with a groove in which the protrusion is to be fitted. With such a structure, assembly can easily be carried out.
The electromagnetic relay according to any of the first to sixth aspects of the invention may further comprise a fixed contact spring block including a fixed side terminal, a leaf spring fastened to the fixed side terminal, and a fixed contact provided on the leaf spring, a moving contact spring block including a moving side terminal, a leaf spring fastened to the moving side terminal and a moving contact provided on the leaf spring, and a card attached to both of the armature and the moving contact spring block for causing the fixed contact and the moving contact to come in contact with or separate from each other depending on a toggle motion of the armature. According to such a structure, a fluctuation in a magnetic characteristic is reduced so that a shock resistance can be enhanced. Moreover, a sensitivity can be regulated easily.
As is apparent from the foregoing, according to the seventh aspect of the invention, an electromagnetic relay comprises a yoke having both ends bent in one direction, a coil portion wound onto a central part between both ends of the yoke, a plate-shaped permanent magnet having a smaller length than that between the ends of the yoke, an auxiliary yoke formed like a plate having a length which is almost equal to that between the ends of the yoke and provided in a direction reverse to the one direction with respect to the permanent magnet, an armature formed to have a greater length than that between the ends of the yoke and attraced into or separated from a magnetic pole portion of the yoke for being rotated depending on an excitation state of the coil portion, a hinge spring for causing both end sides of the armature to be toggled, thereby integrally fixing the permanent magnet, the auxiliary yoke and the armature, a fixed contact plate having a fixed contact, a movable spring having a moving contact opposed to the fixed contact, and a card engaged with the armature for displacing the movable spring such that the moving contact abuts on or separates from the fixed contact depending on a rotating operation of the armature, wherein the hinge spring has a central part attached to a surface in the one direction of the armature and both ends extended from the central part in a direction reverse to the one direction and attached to both side walls of the auxiliary yoke through concavo-convex fitting with the armature and the permanent magnet held, and the auxiliary yoke has a concavo-convex disengagement prevention structure. Therefore, it is possible to provide an electromagnetic relay which changes a characteristic with difficulty even if a vibration or an impact is applied.
According to the eighth aspect of the invention, in the electromagnetic relay according to the seventh aspect of the invention, the hinge spring has a hole on each of both ends and the auxiliary yoke has a protrusion fitted in each hole on the both ends, the protrusion being bent in the direction reverse to the one direction as the disengagement prevention structure. Therefore, the protrusion bent in the direction reverse to the one direction engages the peripheral portion of the hinge spring. Consequently, the protrusion slips off from the hole of the hinge spring with difficulty.
According to the ninth aspect of the invention, in the electromagnetic relay according to the seventh aspect of the invention, the hinge spring has a hole on each of both ends and the auxiliary yoke has a protrusion fitted in each hole on the both ends, the protrusion having, as the disengagement prevention structure, a V-shaped groove for fitting the peripheral portions of the corresponding holes of the ends on the surface in the direction reverse to the one direction. Therefore, the peripheral portion of the corresponding hole is fitted in the V-shaped groove. Consequently, the protrusion slips off from the hole of the hinge spring with difficulty.
According to the tenth aspect of the invention, in the electromagnetic relay according to the seventh aspect of the invention, the hinge spring has a hole on each of both ends and the auxiliary yoke has a protrusion fitted in each hole on the both ends, the protrusion having, as the disengagement prevention structure, a hook-shaped click portion extended in the direction reverse to the one direction. Therefore, the click portion provided on each protrusion engages the peripheral portion of the hole of the hinge spring. Consequently, the protrusion slips off from the hole of the hinge spring with difficulty.
According to the eleventh aspect of the invention, if the opposed distance between both contacts is regulated to be smaller by elastically deforming the movable spring in the direction of the displacement thereof, the sensitivity of the abutting and separating operation of the contacts is increased. To the contrary, if the opposed distance between the contacts is regulated to be longer, the sensitivity of the abutting and separating operation of the contacts is reduced. Consequently, the sensitivity of the abutting and separating operation of the contacts can be regulated. Thus, the sensitivity of the abutting and separating operation of the contacts can be regulated by elastically deforming the movable spring in the direction of the displacement thereof. Therefore, it is not necessary to provide a clearance for sensitivity regulation between the magnetic pole portion of the yoke and the armature, and suction force is not varied. Consequently, the sensitivity of the abutting and separating operation of the contacts can be regulated easily.
According to the twelfth aspect of the invention, in addition to the effects of the electromagnetic relay according to the eleventh aspect of the invention, the movable spring is elastically deformed by the pressing portion in the direction of the displacement thereof. Therefore, the amount of elastic deformation can be regulated by increasing or reducing the pressing force of the pressing portion. Furthermore, the sensitivity of the abutting and separating operation of the contacts can be regulated easily.
According to the thirteenth aspect of the invention, in addition to the effects of the electromagnetic relay according to the twelfth aspect of the invention, the pressing portion is provided on the movable terminal itself. Therefore, it is not necessary to provide the pressing portion by particularly paying attention such that the pressing portion abuts on the movable terminal to generate a mutual interference. Thus, assembly can be carried out easily.
According to the fourteenth aspect of the invention, in addition to the effects of the electromagnetic relay according to the twelfth or thirteenth aspect of the invention, the movable spring locally decreases the spring force of the portion to be pressed by the pressing portion. Therefore, slight elastic deformation can be carried out in the direction of the displacement, and the sensitivity of the abutting and separating operation of the contacts can be regulated with high precision.
According to the fifteenth aspect of the invention, in addition to the effects of the electromagnetic relay according to any of the twelfth to fourteenth aspects of the invention, the press state of the pressing portion can be adjusted by elastically deforming the portion to be pressed by the pressing portion in the direction of the displacement. Therefore, the elastic deformation can be slightly adjusted in the direction of the displacement, and the sensitivity of the abutting and separating operation of the contacts can be regulated with high precision.
According to the sixteenth aspect of the invention, in addition to the effects of the electromagnetic relay according to any of the eleventh to fifteenth aspects of the invention, the current also flows to the contact portion extended from the fixed terminal as well as the fixed contact plate when both contacts abut. Therefore, the current flowing to the fixed contact plate can be decreased so that heat generation can be suppressed.
According to the seventeenth aspect of the invention, in addition to the effects of the electromagnetic relay according to the sixteenth aspect of the invention, the fixed contact plate obtains the prepressures of both contacts. Therefore, the contact pressure can be obtained through the abutment of the contacts.